1). Field of the Invention
This invention relates to a sailing boat and, more specifically, to detection of a force in an elongate direction of a mast of the sailing boat.
2). Discussion of Related Art
Various factors may influence the performance of a sailing boat in racing conditions. One of the factors that influence the performance of the sailing boat is the positioning and shaping of the sails. The positioning and shaping of the sails depend to a large extent on the positioning of a mast of the sailing boat and any bends in the mast. The positioning and shape of the mast can be calculated by measuring, amongst others, a force in an elongated direction along the mast.
In some boats, the force can be increased by sliding more lift plates in between a lower surface of the mast and an upper surface of a mast step of a hull of the boat. The force can be decreased by removing lift plates. A jack is typically used to elevate the mast so that the lift plates can be inserted or be removed. The force can also be increased or decreased by tightening or loosening the rigging.
A rough indication of the force in the mast is obtained by elevating the mast slightly off the lift plates and then measuring the fluid pressure of the jacks that are used to elevate the mast. Once the mast is lowered into its sailing position, there is no way of accurately knowing what the force in that mast is. The disadvantage of this is that there are varying differences between the measured force when the mast is slightly raised, and the actual force when the mast is in its sailing position. A further disadvantage is that force measurements can only be made while the boat is at dock in a stationary position, i.e., not in xe2x80x9creal timexe2x80x9d while sailing.
According to one aspect of the invention, a sailing boat is provided, having a hull, a mast, at least one detector, and an output device. The hull has a mast step. The mast extends upward from the mast step and has a lower end resting in a sailing position on the mast step. The detector detects a variable, indicative of a force exercised by the mast onto the mast step while resting in the sailing position. The output device is connected to the detector, and provides a reading indicative of the variable.
Preferably, no lifting jack is used to keep the mast in the sailing position.
The detector may detect strain deformation. The detector may, for example, include at least one strain gauge or a piezoelectric crystal.
The sailing boat may, for example, include at least a first lift plate. The detector may be secured to the lift plate. The lift plate may be removably located between an upper surface of the mast step and a lower surface of the mast, together with the detector and, after lifting up the mast relative to the mast step, be removable together with the detector from between the upper surface of the mast step and the lower surface of the mast.
The sailing boat may further include a load cell body, wherein the detector is secured to the load cell body, to jointly form a load cell. The load cell body may be mounted to the lift plate, and the detectors may detect strain deformation of a portion of the load cell body.
The load cell body may have a button portion standing proud of a surface of the lift plate, and the detector may detect depression of the button portion toward the lift plate.
The sailing boat may further include a second lift plate having a surface against which the button rests.
The sailing boat may further include a plurality of load cells around the mast.
The sailing boat may further include a plurality of detectors around the mast.
The output device may be mounted to the plate, and a change in the force exercised by the mast causing a direct change in the force displayed on the output device.
The reading provided by the output device is preferably force.
The sailing boat may further include rigging connected between an upper portion of the mast and the hull. The rigging may include a forestay, one or more backstays, and/or shrouds. The forestay may be connected between an upper portion of the mast and a front portion of the hull, and the backstay may be connected between the upper portion of the mast and a rear of the hull, the forestay and the backstay both being under tension to at least partially contribute to the force. The rigging may thus be adjustable to change the force.
According to another aspect of the invention, a combination lift and force detection plate is provided, including a lift plate and detector. The lift plate is insertable between a mast step of a hull and a mast of a sailing ship. The detector may be mounted to the lift plate, to be insertable with the lift plate between and to be removable with the lift plate from between the mast step and the mast. The detector may detect a force exercised by the mast thereon, and provide an output of the force.
The lift plate may have a slot which moves over a post that aligns the mast. The combination may further include a plurality of load cells around the mast.
According to a further aspect of the invention, a method of operating a sailing boat is provided, comprising detecting a force of a mast of a sailing boat on a mast step of a hull of the sailing boat, while the sailing boat is sailing across a body of water, and providing a reading of the force.